I. Field of the Invention
The present invention relates generally to information display systems and, more particularly, to an information display system having an elongated MYLAR (polyethyleneterpthalate) sheet upon which a plurality of longitudinal spaced discrete visual messages are provided.
II. Description of the Prior Art
There are many situations in which it is desirable to display visual information. For example, many buses and other public transportation typically have an information display unit positioned at the front and/or back of the bus which displays information indicative of the bus destination or route.
There have been a number of previously known different types of display systems. In one type, an elongated MYLAR sheet or curtain is contained within the housing around two spaced rollers. The portion of the sheet extending between the rolls is in alignment with a window formed in the housing so that only a portion of the sheet is viewable at any given time. Furthermore, a plurality of discrete visual messages are provided at longitudinally spaced positions along the sheet so that the messages can be changed by changing the position of the MYLAR sheet along the rollers.
One disadvantage of these previously known MYLAR display systems is that it is necessary for the vehicle operator to manually change the position of the MYLAR sheet. In order to do this, it is necessary for the operator to manually move each curtain or sheet using a hand crank or integral drive motor. This is time consuming since buses may have as many as sixteen curtains while subways and trains can have more than thirty two curtains.
There are other information display systems that utilize illuminated lights, or dots, or mechanical dots in a dot matrix pattern in order to form messages. By selectively illuminating the lights, words or phrases are formed on the display.
These previously known display systems with illuminated lamps or dots, however, lack the clarity and definition that can be obtained from the display systems utilizing MYLAR sheets. Such lack of resolution and clarity make the sign much more difficult to read and, for that reason, is undesirable. A still further disadvantage of such systems is that the lamps must be periodically replaced as they wear out which increases the overall cost of the display system and dots prone to mechanical failure.
Other previous automatic curtain type signs utilizing various types of codes have been plagued with high voltage static electricity being generated by the curtains and coupled into the reader electronics causing system malfunction, ect.